Instructor: Seung Bae Im
Closed Book, Closed Notes. Do not write on the back of pages!!
Name:_______________________________
1. (40 Points) Mark your answers on this page.
(a) Given the following IP address in binary, what is its dotted decimal equivalent?
10000100 11110001 10011110 00100100 = ________ . ________ . ________ . ________
(b) For a subnetting scheme which does not allow all 0’s subnet and all 1’s subnet address, choose all the possible values for subnet masks.
____ 128
____ 192
____ 224
____ 240
____ 248
____ 250
____ 252
____ 254
(c) Identify the class of the following IP address: 129.1.2.3
____ Class A
____ Class B
____ Class C
____ Class D
____ Class E
(d) A device has two IP addresses. This device could be ? Mark all that apply.
____ a Computer
____ a Bridge
____ a Router
____ a Repeater
(e) A host with IP address 132.241.158.36 with the subnet mask of 255.255.255.224 sends a message to a host with IP address 132.241.158.42. Does the message travel through any router?
____ Yes
____ No
(f) A host with IP address 132.241.158.36 with the subnet mask of 255.255.255.240 sends a message to a host with IP address 132.241.158.48. Does the message travel through any router?
____ Yes
____ No
(g) Which one should be the “supernet mask” to combine 8 class C address blocks?
____ 255.255.255.224
____ 255.255.255.240
____ 255.255.248.0
____ 255.255.255.0
____ None of the above
(h) A subnet mask of 255.255.224.0 allows how many hostids per subnet?
____ 29 – 2
____ 210 – 2
____ 211 – 2
____ 212 – 2
____ 213 – 2
____ None of the above
(i) Who is responsible for “reassembling” of “fragmented IP datagrams”?
____ Source host
____ A router at the destination network
____ A destination host
(j) Your company has a Class C address of 193.123.33.0. You need to divide the given address space into different sizes using VLSM: two subnets with 62 hosts each and four subnets with 30 hosts each. What subnet masks do you need to achieve it?
____ 255.255.255.192
____ 255.255.255.224
____ 255.255.255.240
____ 255.255.255.248
____ 255.255.255.252
2. (50 Points) 3 point each unless otherwise noted.
(a) With a diagram compare the layers between OSI model and TCP/IP model. Clearly mark corresponding layers of each model. Also, on the TCP/IP model diagram, write the name of protocols on each layer.
(b) Describe “Multiplexing/demultiplexing” of a protocol layer using application layer and TCP layer interactions as an example. Include the term: SAP(Service Access Points), Port#
(c) Describe TCP’s flow control mechanism including the term, “credt”.
(d) An IP module(on a host or a router) uses “MTU(Maximum Transfer Unit) table). Describe how the IP module uses this table.
(e) Describe why TCP needs 3-way handshaking for connection establishment.
(f) Describe why all 1’s and all 0’s are not useable in hostid portion of IP address.
(g) (12 points) We say that “client-server computing” is achieved using TCP (or UDP) socket-to-socket communication. Describe “client-server computing” including the following terms: Concurrent server, well-known port number, server’s IP address, client, ephemeral port number, client IP address, , child process.
(h) Draw the hierarchical diagram of DNS tree and name each level.
(i) What is the main function of ICMP protocol?
(j) (6 points) Internet address space(IPv4) is running out(not many addresses are left to be assigned). There are three main solutions: 1) CIDR 2) NAT 3) IPv6 Describe how each of them helps to solve the problem.
3. (10 Points) Routing:
(a) Point out the difference(s) between “routing protocol” and “routed protocol”.
(b) Point out the difference(s) between “IGP” and “EGP”.
(c) (6 points) Point out the differences between “Distance vector routing” and “Link state routing”.